TRIPOLI, Libya -- A defiant Muammar al-Qaddafi threatened Friday to carry out attacks in Europe against "homes, offices, families," unless NATO halts its campaign of airstrikes against his regime in Libya.

The Libyan leader, sought by the International Criminal Court for a brutal crackdown on anti-government protesters, delivered the warning in a telephone message played to thousands of supporters gathered in the main square of the capital Tripoli.

It was one of the largest pro-government rallies in recent months, signaling that Qaddafi can still muster significant support. A green cloth, several hundred meters long and held aloft by supporters, snaked above the crowd filling Tripoli's Green Square. Green is Libya's national color.

Qaddafi spoke from an unknown location in a likely sign of concern over his safety. Addressing the West, Qaddafi warned that Libyans might take revenge for NATO bombings.

"These people (the Libyans) are able to one day take this battle ... to Europe, to target your homes, offices, families, which would become legitimate military targets, like you have targeted our homes," he said.

"We can decide to treat you in a similar way," he said of the Europeans. "If we decide to, we are able to move to Europe like locusts, like bees. We advise you to retreat before you are dealt a disaster."

It was not immediately clear whether Qaddafi could make good on such threats.

In the past, Qaddafi supported various militant groups, including the IRA and several Palestinian factions, while Libyan agents were blamed for attacks in Europe, including a Berlin disco bombing in 1986 and the downing of Pan Am Flight 103 over Lockerbie, Scotland, that killed 270 people, mostly Americans. Libya later acknowledged responsibility for Lockerbie.

In recent years, however, Qaddafi was believed to have severed his ties with extremist groups when he moved to reconcile with Europe and the United States.

Al-Qaida and other jihadi groups have opposed Qaddafi since he cracked down in the late 1990s on the Islamist Libyan Islamic Fighting Group which sought to replace his regime with an Islamic state.

In Tripoli, supporters unleashed repeated barrages of defiant gunfire into the air after Qaddafi's speech.

A series of powerful explosions later rattled the heart of the capital as supporters cheered and honked car horns in the street. Black smoke could be seen rising from the area near Qaddafi's Bab al-Aziziya compound. It wasn't clear whether the blasts signaled renewed NATO airstrikes or were bursts of celebratory fireworks.

A U.S. State Department spokesman, Mark Toner, said the U.S. would take Qaddafi's threat of attacks seriously, as his regime carried out such actions in the past. Toner said he did not know if there was intelligence to indicate Qaddafi's regime would be able to carry out such attacks.

"This is an individual who's obviously capable of carrying these kinds of threats, that's what makes him so dangerous, but he's also someone who's given to overblown rhetoric," Toner told a news conference in Washington.

Friday's rally came just four days after the International Criminal Court issued arrest warrants for Qaddafi, his son Seif al-Islam and Libyan intelligence chief Abdullah al-Sanoussi for crimes against humanity. International prosecutors allege government troops fired on civilian protesters during anti-Qaddafi street demonstrations earlier this year.

The popular uprising has since turned into a protracted civil war, with anti-government rebels controlling much of eastern Libya and parts of Libya's western mountains. NATO has been bombing government-linked targets since March.

In his speech Friday, Qaddafi denounced the rebels as traitors and blamed them for Libya's troubles.

He said Libyans who fled to neighboring Tunisia are now "working as maids for the Tunisians."

"Tunisians used to work for Libyans. What brought you to this stage? The traitors," he added.

He called on his supporters to march on rebel strongholds, including the western mountain area and the port city of Misrata, both in the otherwise Qaddafi-controlled western Libya. "We must end this battle fast," he said of the attempts to oust him from power, which began with an uprising in mid-February.

Qaddafi's speech signaled that mounting international pressure, including the arrest warrants against him, have made him only more defiant.

His son, Seif al-Islam, who like his father is a wanted man, denied in a TV interview that either of them ordered the killing of civilian protesters in Libya, as prosecutors charge.

The younger Qaddafi told Russian news channel RT in an interview posted online Friday that "most of the people" died when they tried to storm military sites, and that guards fired on them under standing orders to protect the bases and themselves.

However, documents from the International Criminal Court outline multiple instances in which the tribunal prosecutors allege government troops fired on civilian protesters during anti-Qaddafi street demonstrations earlier this year.

The younger Qaddafi had once been viewed as a reformer by the West and was being groomed as a possible successor to his father.

Seif al-Islam wore a thick beard and traditional clothes in the interview. He denounced the international court seeking his arrest as controlled by the NATO countries now bombing Libya.

"This court is a Mickey Mouse court ... For me to be responsible for killing people, it was a big joke," he told the Russian state-funded network.

The Netherlands-based tribunal on Monday issued arrest warrants against the Libyan leader, his son Seif al-Islam and intelligence chief Abdullah al-Sanoussi.

The three are accused of orchestrating the killing, injuring, arrest and imprisonment of hundreds of civilians during the first 12 days of an uprising to topple Muammar al-Qaddafi from power, and for trying to cover up their alleged crimes.

Presiding Judge Sanji Monageng of Botswana has said that hundreds of civilians were killed, injured or arrested in the crackdown, and there were "reasonable grounds to believe" that Qaddafi and his son were both responsible for their murder and persecution.

But Seif al-Islam denied that he and his father specifically ordered protesters to be killed.

"Of course not," he said, arguing that government troops fired on protesters out of self-defense.

"Nobody ordered. Nobody. The guards fired. That's it. ... The guards were surprised by the attacking people and they start ... firing. They don't need an order to defend themselves," he said.

Seif al-Islam accused Western nations of intervening in Libya because they are after the country's oil and other resources. He said the goal is "to control Libya," and he vowed to fight on.

"Nobody will give up. Nobody will raise the white flag," he said. "We want peace, but if you want to fight, we are not cowards. ... We are going to fight."